Claims for Patent: 4,755,375

Summary for Patent: 4,755,375

Title:	Method and kit for the selective labeling of red blood cells in whole blood with TC-99M
Abstract:	Disclosed herein are a method and kit for the preparation of .sup.99m Tc labeled red blood cells using whole blood in a closed sterile system containing stannous tin in a form such that it will enter the red blood cells and be available therein for the reduction of technetium.
Inventor(s):	Srivastava; Suresh C. (Setauket, NY), Babich; John W. (Redhill, GB2), Straub; Rita (Brookhaven, NY), Richards; Powell (New Bern, NC)
Assignee:	Associated Universities, Inc. (Washington, DC)
Application Number:	06/853,120
Patent Claims:	1. A method of labeling red blood cells with .sup.99m Tc consisting essentially of: A. supplying a sample of whole blood, including plasma and the red blood cells to be labeled, to a container having therein under sterilized conditions a lyophilized stannous ion complex with a tin content of from 5-1000 .mu.g together with a tin complex stabilizer and incubating the mixture for a sufficient time to permit some of the stannous ion complex to pass through the membranes of the red blood cells into the cells; b. subjecting the resulting suspension of red blood cells in plasma to the action of an oxidizing agent to convert substantially all of the stannous tin in the plasma to stannic tin; C. incubating the avove suspension with a chelating agent for both stannic and residual stannous tin in the plasma to form tin chelates; and D. incubating the resulting suspension with a source of .sup.99m Tc pertechnetate ion, in a form in which the ion will pass through the cell membranes of the red blood cells into the red blood cells, for a sufficient period of time to permit the stannous ions within the red blood cells to reduce the technetium to a lower valence state in which it will not pass out of the cells through the cell membrane, thereby labeling the cells with .sup.99m Tc. 2. A method as in claim 1 wherein the whole blood is treated with an anti-coagulant agent before it enters the container. 3. The method of claim 2 wherein the anti-coagulant agent is heparin. 4. A method as in claim 1 wherein said container also contains an anti-coagulant so that the whole blood is prevented from coagulating by the action of said anti-coagulant in the container. 5. A method as in claim 1 wherein the stannous ion is complexed with a complexing agent selected from the group consisting of alkali metal citrates, alkali metal glucoheptonates, alkaline earth metal citrates, alkaline earth metal glucoheptonates, alkali metal tartrates, alkali metal pyrophosphates, organic diphosphonates, ethylenediaminetetraacetic acid, dimercaptosuccinic acid and diethylenetriaminepentaacetic acid. 6. The method of claim 5 wherein the complexing agent is sodium citrate. 7. The method of claim 5 wherein the complexing agent is sodium glucoheptonate. 8. A method of claim 1 wherein the tin complex stabilizer is a reducing sugar. 9. The method of claim 8 wherein the reducing sugar is dextrose. 10. A method of claim 1 wherein the oxidizing agent is an alkali metal hypochlorite. 11. A method of claim 1 wherein the chelating agent is selected from the group consisting of disodium ethylenediaminetetraacetic acid, calcium disodium ethylenediaminetetraacetic acid, and acid citrate dextrose. 12. A method of claim 1 wherein the source of the .sup.99m Tc pertechnetate ion is an alkali metal pertechnetate. 13. The method of claim 1 wherein the complexing agent is selected from the group consisting of sodium citrate and sodium glucophetonate, the tin complex stabilizer is dextrose, the oxidizing agent is an alkali metal hypochlorite, the chelating agent is selected from the group consisting of disodium ethylenediaminetetraacetic acid, calcium disodium ethylenediaminetetraacetic acid, and acid citrate dextrose, and the source of the .sup.99m Tc pertechnetate ion is an alkali metal pertechnetate. 14. A method as in claim 13 wherein the oxidizing agent is sodium hypochlorite and the source of .sup.99m Tc pertechnetate ion is sodium pertechnetate. 15. A method as in claim 1 wherein the incubation of Step D is conducted at an elevated temperature to damage the labeled red blood cells. 16. A method as in claim 13 wherein the incubation of Step D is conducted at an elevated temperature to damage the labeled red blood cells.